The potential perils have been played up in the press, but if simple common sense is used when disposing of a broken CFL, the resulting exposure to mercury is equivalent to a mere nibble of tunaLighting professionals arepresumably aware thatused CFLs are supposedto be recycled, and not just sentto landfills, because of the smallamount of toxic mercury they contain.

But what do you advise yourclients when they break a lamp?And just how dangerous is themercury inside?You may have heard that cleanupcosts are exorbitant and that themercury vapor concentration froma broken lamp is unsafe. Actually,the amount of mercury that you arelikely exposed to after breaking alamp is no more than you subjectyourself to when eating a bite oftuna. In this paper, we review theconcerns, describe why we believethat the fish comparison is valid andshow that the real risk is negligible.

Let’s start with the reports of exorbitantclean-up costs and dangerousmercury vapor levels. In April2007, Brandy Bridges accidentallybroke a CFL in her daughter’s bedroomand was left wondering whatto do next. [1] After several referrals,she phoned the Maine Departmentof Environmental Protection(MDEP), which sent a specialistto her home a day later.

Airborneconcentrations of mercury weregenerally low, but measurementsin two areas—a 1-ft area aroundthe breakage and a nearby bag oftoys where some lamp fragmentshad fallen—exceeded the state’s airquality standard. When Bridgesexpressed concern about longtermexposure, she was referredto a commercial clean-up contractor;the estimate for a professionalclean-up was $2,000.

This incident was quickly seizedupon as an argument against theuse of CFLs. Why should consumersbear the risk of introducing apotential safety hazard into theirown homes just to save a littleenergy? Against health concernsand clean-up costs on this scale, alower utility bill and the satisfactionfrom a little environmentalismseem meager encouragement.In response to public outrage, especiallyin the blogosphere, MDEPposted a reply documenting itsassurances to Bridges that, in hercase, “potential mercury exposurewould be very low and likely ofnegligible health concern.”

Unfortunately,this assurance is apparentlytrue only as long as brokenCFLs are “properly cleanedup.”[2] These responses are hardlyless alarming. Would exposure bepotentially hazardous under differentcircumstances? And whatdoes proper clean-up entail?MDEP couldn’t find the informationto actually answer these questions,so they ran a study whichexamined 45 different breakage/clean-up scenarios.[3]

They foundthat altering the ventilation conditions,cleaning methods and equipment,sample CFL, and breakageconditions and surface (e.g., hardwoodfloor versus carpet), resultedin average first-hour mercuryvapor concentrations that variedby a factor of 600.

Many of theseconcentration levels exceeded thestate air quality standard, and thereport concluded that “…homeownersconsider not utilizing fluorescentlamps…where they couldeasily be broken, in bedroomsused by infants, small children orpregnant women…” and, should alamp be broken over a carpet, that“…homeowners consider removalof the area of the carpet where thebreakage occurred as a precaution,particularly in homes with infants,small children, or pregnant women.”

This is not much better than the $2,000 clean-up, and, if takenseriously, is likely to discouragea lot of people from consideringCFLs at all.A QUES TION OF EXPOSUREThose of us who remembermercury thermometers, whichcontained 100 or more times theamount of mercury in a CFL, maywell wonder how we ever survived.In fact, the use of the stateair quality standard to determinethe acceptable level for a one-timeor infrequent exposure is extremelyconservative.

The state standardis based on an estimate of the NoObservable Adverse Effects Level(NOAEL) for continuous (lifetime)exposure. The MDEP justifiesusing this ambient air quality(AAQ) standard for a single exposurebecause of a lack of informationon the effects of prenatal exposure:

“An important issue forwhich there are no data is the relativeimportance of a short spikein exposure versus a longer-termlower exposure in producing toxicity.The U.S. EPA considers that asingle exposure may be sufficientto produce effects in a developingorganism because of the recognitionof potential critical windowsof vulnerability.”

Based on thislogic, a short spike in exposure could be as short as a single breath. MDEP, without any discussion of the issue, confines its analysis tosituations where the average level exceeds the AAQ for one hour.